The impact of the use of the isolated echogenic intracardiac focus as a screen for Down syndrome in women under the age of 35 years

OBJECTIVE: The purpose of this study was to determine the public health imp act of the routine offering of amniocentesis to women under the age of 35 y ears who have an isolated fetal echogenic intracardiac focus on second trim ester ultrasound scan. STUDY DESIGN: A decision analytic model was designed that compared the acce pted standard of second trimester triple marker screen for Down syndrome to a policy In which amniocentesis with an Isolated echogenic intracardiac fo cus on ultrasound in addition to the triple marker screen is offered to all women in the United States who are < 35 years of age. A sensitivity of 20% , an echogenic intracardiac focus screen positive rate of 5%, and a risk of Down syndrome of 1:1000 were assumed. A sensitivity analysis was performed that varied the screen positive rate, the sensitivity of echogenic intraca rdiac focus for Down syndrome, and the prescreen risk for Down syndrome in the population. RESULTS: With the baseline sensitivities, rates, and risks, the use of isol ated echogenic intracardiac focus as a screen would result in an additional 118,146 amniocenteses performed annually to diagnose 244 fetuses with Down syndrome. These amniocenteses would result in 582 additional miscarriages. It would be necessary to perform 485 amniocenteses that would result In 2. 4 procedure-related losses for each additional Down syndrome fetus that was identified. CONCLUSION: Although the echogenic intracardiac focus appears to be associa ted with a small increased risk of Down syndrome, its use as a screening to ol in low-risk populations would lead to a large number of amniocenteses an d miscarriages to identify a small number of Down syndrome fetuses.